Feign 客户端的使用 二

一、Feign的使用（客户端调用 json/xml格式的接口）

1.服务端接口编写

<parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.0.2.RELEASE</version>
  </parent>

  <dependencies>
      <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-web</artifactId>
      </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.jaxrs</groupId>
      <artifactId>jackson-jaxrs-xml-provider</artifactId>
      <version>2.9.0</version>
    </dependency>
  </dependencies>

　　@RequestMapping(value = "/hello", method = RequestMethod.GET)
    public String hello() {
        return "hello world";
    }

    @RequestMapping(value = "/person/create", method = RequestMethod.POST,
            produces = MediaType.APPLICATION_JSON_VALUE,
            consumes = MediaType.APPLICATION_JSON_VALUE)
    public String createPerson(@RequestBody Person person) {
        System.out.println(person.getName() + "~~~~~~~" +person.getAge());
        return "success, id:" + person.getId();
    }

    @RequestMapping(value = "/createXmlPerson/create", method = RequestMethod.POST,
            produces = MediaType.APPLICATION_XML_VALUE,
            consumes = MediaType.APPLICATION_XML_VALUE)
    public String createXmlPerson(@RequestBody Person person) {
        System.out.println(person.getName() + "~~~~~~~" +person.getAge());
        return "<result><message>success</message></result>";
    }

2.客户端编写

（1）导入jar包

<dependencies>
    <dependency>
      <groupId>io.github.openfeign</groupId>
      <artifactId>feign-core</artifactId>
      <version>9.5.0</version>
    </dependency>

    <dependency>
      <groupId>io.github.openfeign</groupId>
      <artifactId>feign-gson</artifactId>
      <version>9.5.0</version>
    </dependency>

    <!--配置xml客户端-->
    <dependency>
      <groupId>io.github.openfeign</groupId>
      <artifactId>feign-jaxb</artifactId>
      <version>9.5.0</version>
    </dependency>

    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.16.20</version>
    </dependency>

    <dependency>
      <groupId>javax.xml.bind</groupId>
      <artifactId>jaxb-api</artifactId>
      <version>2.3.0</version>
    </dependency>

    <!--httpclient-->
    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.5</version>
    </dependency>
  </dependencies>

（2）编写客户端测试代码

public interface ClientInterface {

    @RequestLine("GET /hello")
    public String hello();

    @RequestLine("GET /person/{id}")
    public Person getPerson(@Param("id") Integer id);

    @RequestLine("POST /person/create")
    @Headers("Content-Type: application/json")
    public String createPerson(Person person);

    @RequestLine("POST /createXmlPerson/create")
    @Headers("Content-Type: application/xml")
    public Result createXmlPerson(Person person);
}

public static void main(String[] args) {
        //hello
        ClientInterface helloClient = Feign.builder().target(ClientInterface.class, "http://localhost:8080");

        String hello = helloClient.hello();
        System.out.println(hello);

        //json 创建 Person
        ClientInterface creatPersonInter = Feign.builder()
                .encoder(new GsonEncoder())
                .target(ClientInterface.class, "http://localhost:8080");

        Person person = new Person();
        person.setAge(18);
        person.setId(1);
        person.setName("admin");

        String result = creatPersonInter.createPerson(person);
        System.out.println("result:" + result);

        //xml 创建 Person
        JAXBContextFactory jaxbContextFactory = new JAXBContextFactory.Builder().build();
        ClientInterface xmlClient = Feign.builder().encoder(new JAXBEncoder(jaxbContextFactory))
                .decoder(new JAXBDecoder(jaxbContextFactory))
                .target(ClientInterface.class, "http://localhost:8080/");

        Person person1 = new Person();
        person1.setAge(18);
        person1.setId(1);
        person1.setName("admin");
        Result result2 = xmlClient.createXmlPerson(person1);
        System.out.println("result:"+result2.getMessage());
    }

二、自定义Feign客户端

1.编写myClient

import feign.Client;
import feign.Request;
import feign.Response;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Collection;
import java.util.HashMap;

public class MyClient implements Client {
    @Override
    public Response execute(Request request, Request.Options options) throws IOException {
        try {
            System.out.println("自定义的client");

            //创建一个默认的客户端
            CloseableHttpClient httpClient = HttpClients.createDefault();

            //获取调用的http方法
            final String method = request.method();

            //创建一个HttpClient 的 HttpRequest
            HttpRequestBase httpRequestBase = new HttpRequestBase() {
                @Override
                public String getMethod() {
                    return method;
                }
            };

            //设置请求地址
            httpRequestBase.setURI(new URI(request.url()));

            //执行请求，获取响应
            HttpResponse httpResponse = httpClient.execute(httpRequestBase);

            //获取响应的内容
            byte[] body = EntityUtils.toByteArray(httpResponse.getEntity());

            //将HttpClient d的响应对象转换为Feign的Response
            Response response = Response.builder()
                    .body(body)
                    .headers(new HashMap<String, Collection<String>>())
                    .status(httpResponse.getStatusLine().getStatusCode())
                    .build();
            return response;
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }
        return null;
    }
}

2.编写MyClientTest测试

public static void main(String[] args) {
        ClientInterface clientInterface = Feign.builder()
                .client(new MyClient())
                .target(ClientInterface.class, "http://localhost:8080");

        String hello = clientInterface.hello();
        System.out.println(hello);
    }